1999 Explorer Transfer Case Leak

[bob3rt]

Hi, I have a 1999 Explorer V8 AWD and I have a leak coming from the front of the transfer case. I was hoping to get some ideas on what the issue could be and how I would go about fixing it. Would there be any harm in just topping off the oil every once in a while and just let it leak? I've also attached some pictures.

Thanks!

 

[imp]

@bob3rt
Looks suspiciously like dirty fluid, more likely transmission than transfer case. Either way, ya yank out the transfer case, replace the transmission output shaft seal and the t-case input shaft seal, replace the gasket, throw it back together. Do you know for a fact that the t-case is losing oil? If so, yes, you can keep topping it up. imp

 

[bob3rt]

@bob3rt
Looks suspiciously like dirty fluid, more likely transmission than transfer case. Either way, ya yank out the transfer case, replace the transmission output shaft seal and the t-case input shaft seal, replace the gasket, throw it back together. Do you know for a fact that the t-case is losing oil? If so, yes, you can keep topping it up. imp

Do you know if there are any guides on here showing how to replace the seals?

I'm not sure whether it is the transmission or the transfer case, but I've been checking the transmission fluid level via the dip stick and it seems okay. I just assumed it was the transfer case. I haven't actually had the opportunity to check the transfer case since I would have to get the fill hole opened up. I don't have easy access to a work area at the moment.

 

[transman304]

There is no output shaft seal. There is a gasket between extension housing and transfer case. Might try just snugging up the bolts. This is the gasket needed.

 

[imp]

There is no output shaft seal. There is a gasket between extension housing and transfer case. Might try just snugging up the bolts. This is the gasket needed.
View attachment 97239

@transman304
Begging to differ, sir, my 5R55S most certainly has a transmission output shaft seal, as shown in the view below from the Ford Shop Manual. As can be seen, both 4X4 and 4X2 use a seal in that location. The seals are part #s 100 and 97. If no seal were present there, the adaptor would fill with transmission fluid which would pass the lip of the Transfer Case input shaft, eventually trying to establish an equal level of fluid in both. That would be a bad thing......imp

EDIT: Just noticed the OP has an earlier transmission than 5R55S, possibly the "E" or "N", with which I am not familiar. IF those use no trans. output shaft seal, the Transfer Case input shaft seal must be double-lipped, having lips facing both outwards and inwards.

 

[bob3rt]

So I was able to confirm that the fluid leaking out is from the transmission. I opened up the t-case fill hole and the fluid inside was very dirty. The oil leaking is pretty clean so I'm almost positive it didn't come from the t-case. I also tried torquing down the bolts. I was able to turn them about a quarter turn which seems to have slowed the leak, but not stopped it. Are you able to confirm if I need to change the output shaft seal or just a gasket?
Thanks

 

[imp]

So I was able to confirm that the fluid leaking out is from the transmission. I opened up the t-case fill hole and the fluid inside was very dirty. The oil leaking is pretty clean so I'm almost positive it didn't come from the t-case. I also tried torquing down the bolts. I was able to turn them about a quarter turn which seems to have slowed the leak, but not stopped it. Are you able to confirm if I need to change the output shaft seal or just a gasket?
Thanks

@bob3rt
If I recall correctly, my own 2004's adaptor uses a gasket, but factory provided a "weep" hole, tiny, to equalize pressure within the adaptor, between the two seals present. No amount of tightening will stop that weep hole from allowing oil to exit the cavity. Your transmission is an earlier model, so I cannot speak 100%. Regardless of the leak source, you need to remove the Transfer Case and carefully scrutinize the difference in oils between the trans. and TC to determine which seal is leaking. While it's apart, why in the world would one NOT replace both seals, as well as the gasket? T-case removal is no big thing, it's lightweight, lifts out and down by hand, about 60#. imp

 

[transman304]

Imp, the 5R55E has no seal The W/S/N models didn't come out until 2002. And yes by all means the do have seals. Sorry for the confusion. That's why I posted the picture of the gasket needed. Th OP states it is a 1999 which makes it a 5R55E. The 5R55W/S don't even use a transmission to transfer case adaptor. The 5R55N is 2wd application.

This is all based on it being a 1999 model year.
UPDATE: 1999 5.0 will be a 4R70W transmission. Still no output seal. Just a gasket.

 

[imp]

Imp, the 5R55E has no seal The W/S/N models didn't come out until 2002. And yes by all means the do have seals. Sorry for the confusion. That's why I posted the picture of the gasket needed. Th OP states it is a 1999 which makes it a 5R55E. The 5R55W/S don't even use a transmission to transfer case adaptor. The 5R55N is 2wd application.
View attachment 97266
This is all based on it being a 1999 model year.
UPDATE: 1999 5.0 will be a 4R70W transmission. Still no output seal. Just a gasket.

@transman304
Thank you for clarifying that. In the pic above, the flat plate, #99, Ford calls "Adaptor", but in reality it simply allows the mating to the T-case while closing off the back of the Transmission Case. At any rate, my "S" model had the gasket from the factory. imp